Thanks for you thoughts on this.

Lots of Lamproite in Arizona, a major host rock for diamonds after Kimberlite. There is some Kimberlite here too.

Somewhere very long ago I read that the largest Kimberlite pipe in the US - or was it in the world? - is in Arizona, but it is barren, even though it hosts lots of indicator minerals and some semi precious stones. I think it's up north on the Navajo reservation.

But you're right. I never heard of native diamonds in Arizona, though there are small occurrances in other Western states.

Other gemstone is a possibility as Arizona is a leading producer, but I'm thinking something with industrial applications.

VP